Asanuma graduated from Waseda University's department of Political Economy in 1923. On 1 December 1925, at the age of 26, he was appointed secretary-general of Japan's first unified proletarian party, the
Farmer-Labour Party, but the party was forcibly dissolved by the government just one hour after its formation, citing the authority of the recently passed
Peace Preservation Law. In 1926, Asanuma was one of the main founders of the similarly named
Japan Labour-Farmer Party, as part of his efforts to link urban labor movements with rural peasant's movements. However, Asanuma left the party after it split into right, center, and left factions, and became involved in tenant organizing and the
Labour-Farmer movement. In 1932, the fragmented proletarian parties were united to form the
Social Masses Party, which Asanuma also joined.
Shift to National-Socialism and the war period Deeply admiring secretary-general
Hisashi Asō's character, he supported Asō's national-socialist line aiming for social reform through cooperation with the military. Thereafter, Asanuma took a position supporting the military's war policies. Representing the
Social Masses Party, Asanuma was elected to the
Tokyo City Council in 1933 and to the
House of Representatives for the first time in the
1936 Japanese general election. In 1938, when the Japanese Diet passed the
State General Mobilization Law and other bills, Asanuma, representing the
Social Mass Party, spoke in favor of them and served as a member of the National Mobilization Deliberation Council. In 1939, Asanuma participated in a Japanese parliamentary delegation to the Inter-Parliamentary Union conference in
Oslo,
Norway (August 1939), traveling through the
United States and
Europe from June to October. During the voyage, he read extensively from
Ikki Kita (including
History of Chinese Revolution) and held frequent discussions with
Reikichi Kita (younger brother of Ikki Kita, also a delegation member). He expressed strong admiration for Ikki Kita's passionate nationalism and for
Shūmei Ōkawa (whose
2600 Years of the Japanese History he read, noting that its patriotic ideas "seeped into his body"). These readings reinforced his vision of a new East Asian order as "supra-national regionalism" rather than imperialism. While in Europe, Asanuma observed wartime preparations in
Germany and the outbreak of World War II (
Germany's invasion of Poland on 1 September 1939, which he learned of in
Berlin). He recorded factual impressions of
Hitler's oratory and the disciplined atmosphere in Nazi Germany at the time, viewing the European conflict pragmatically as a potential opportunity for Japan's independence and ethnic unity in Asia (not as ideological endorsement). These were his contemporaneous observations during the crisis. That same year,
Asō's sudden death deprived Asanuma of his spiritual pillar, causing him deep anguish. He declined to run in the 1942 wing-election, temporarily withdrawing from national politics. This decision later exempted him from postwar public office purges. In 1942, he ran for Tokyo City Council but lost due to interference by authorities. Following the establishment of the Tokyo metropolitan system, he ran in the first Tokyo Metropolitan Assembly election in 1943, won a seat, and was appointed vice-chairman. During the March 1945 Tokyo air raids, Asanuma survived in his Dōjunkai apartment by removing flammable items and covering windows with wet straw mats to protect against shattering glass and fire. He later recalled the experience with lingering fear, saying it still made his hair stand on end. He listened to the
Gyokuon-hōsō (Jewel Voice Broadcast announcing
Japan's surrender) in his apartment in Fukagawa. In January 1951, while Inejirō was being re-appointed secretary-general at a Japan Socialist Party congress held in Waseda University Lecture Hall, he was privately informed of his father’s death. He chose not to announce it publicly at the congress, fearing it would be seen as a bad omen for the party. The next day he chaired the funeral of fellow socialist Minekubo Manryō before traveling to Miyake Island for his father’s funeral. Reflecting later, he wrote: In January of the 25th year [Shōwa 25 = 1950], at the party congress in Waseda University Lecture Hall, my father's death was announced to me. This was the congress where I was re-appointed as secretary-general, and announcing my father's death at that congress—while I don't necessarily believe in omens—seemed bad for the party, so I kept it secret. The next day there was the party funeral of the late Minekubo Manryō, and since I was serving as funeral committee chairman, I finished the funeral and only then headed to Miyake Island. There was no regular ferry service at the time, so I returned to Miyake Island on a small boat of about 100 tons, but in my haste I left my morning coat behind in a taxi along the way. Was this divine punishment for defying my father to become a politician, or for failing even to be at his deathbed? Such failures happened too. Due to his role as secretary-general, when internal conflicts arose, he often acted as a mediator, pacifying both sides with "maa maa" (calm down), earning him the nickname "Maa-maa Koji" (まあまあ居士; roughly "Calm-Down Lay Practitioner" or "There-There Hermit"). His long tenure as secretary-general without ascending to chairman also led to the nickname "perpetual secretary-general" (万年書記長; Mannen Shokichō, lit. "ten-thousand-year secretary-general"). In late 1958, Asanuma participated in a suprapartisan initiative supporting the repatriation of
Zainichi Koreans from Japan to
North Korea. This took place at a time when Zainichi Koreans faced legal uncertainty, discrimination, and economic hardship following Japan’s colonial rule of Korea and the division of the Korean Peninsula during the
Cold War. On 17 November 1958, the "Association for Cooperation on the Repatriation of Korean Residents in Japan" (在日朝鮮人帰国協力会) was formally launched, bringing together figures from across Japan’s political spectrum, with Asanuma, former conservative Prime Minister
Ichirō Hatoyama, and Japan Communist Party leader
Kenji Miyamoto, among its prominent supporters. At the time, North Korea promoted itself as willing to accept returnees and the group framed the effort as a humanitarian issue respecting individuals' right to return to their homeland, though knowledge of conditions in North Korea was limited. The group’s activities contributed to the Japanese government’s approval of the program, with repatriation beginning in 1959.
Views on the Emperor System Despite his socialist politics and sharp criticism of Western imperialism, Asanuma was known for his deep respect for
emperor Hirohito and the
imperial family. He maintained a household Shinto altar (
kamidana) in his apartment living room and performed a daily clapping reverence toward it as a gesture of devotion. In addition to private rituals, scholar Umezawa Shohei notes that Asanuma performed
yōhai (remote worship/bowing from a distance) toward the imperial palace every morning. This practice stood in contrast to the
Japanese Communist Party's calls to "overthrow the
emperor system", which Asanuma disliked and actively rejected despite his socialist affiliations. Asanuma, serving as organizational minister, opened proceedings by declaring "Now, let us perform remote worship toward the imperial palace" and called on the audience to stand and bow. More than half the participants joined him, though some jeered in protest. As a right-wing Socialist Party secretary-general, Asanuma stated that the issue of the emperor's abdication should be decided by the emperor himself, demonstrating deference to imperial autonomy on sensitive postwar matters. Asanuma's respect for the emperor aligned with some right-leaning socialists' views, seeing the imperial institution as a symbol of national unity and ethnic harmony rather than oppression (unlike foreign monarchies). They also underscored the continuity in Asanuma's thought: a consistent opposition to external domination of Asia alongside an attachment to Japan's traditional national character. He viewed the emperor system as non-exploitative and capable of fostering social equilibrium, reflecting a "natural national sentiment" beyond ideological theory. This episode has been cited as evidence of his understanding of Japan's national polity and his "patriot" qualities within socialism.
Visits to China 1957 visit In April 1957, Asanuma led the Japan Socialist Party's First Goodwill Mission to
China as its head delegate. Upon arrival, he publicly expressed deep remorse for Japan's invasion of China, stating that the delegation felt profound reflection for failing to prevent the war of aggression that had inflicted great suffering on the Chinese people. This trip laid groundwork for subsequent JSP–China exchanges, including Asanuma's second visit in 1959.
1959 visit In March 1959, as leader of the second JSP delegation to China, Asanuma endorsed the PRC's "
One China" policy and declared "American imperialism is the common enemy of the peoples of Japan and China". The speech draft was prepared by the left-wing
Kenichi Hirosawa, whom Asanuma pejoratively called "gokusa" (extreme left). The explicit naming of "American imperialism" as the "enemy" caused a major stir domestically and internationally. The
Liberal Democratic Party's
Takeo Fukuda immediately sent a protest telegram, successfully framing it as "Asanuma's gaffe". The image of Asanuma disembarking at
Haneda Airport wearing a Chinese worker's cap (rather than a full
Mao suit, as sometimes mischaracterized in popular retellings) drew criticism from the right wing, public opinion, and even within the party. Right-wing delegate Sone Masaru and others stated they could not agree with the secretary-general's attitude. Left-wing chairman
Mosaburō Suzuki reportedly scolded Hirosawa, saying "What on earth were you doing as Asanuma's secretary?" During the visit, Asanuma also expressed his view on the true nature of humanity: "I believe that the true nature of humanity is not one of conflict between people, nor one of class conflict, nor one of nations fighting and shedding blood. I believe that the true nature of humanity lies in resolving these problems as quickly as possible and mobilizing all our strength to fight against great Nature." He linked this ideal to the realization of socialism. According to a 22 September 2015
Sankei Shimbun online article, shortly after returning, Asanuma was questioned by U.S. Ambassador
Douglas MacArthur II and backed off his comments after being shouted down while attempting to explain. However, according to an interview by Akihisa Hara with
Seiichi Katsumata, Asanuma refused to retract his statement, leading to a prolonged argument and cancellation of the planned meeting. According to the official JSP account "Maishin: The Struggle of Inejirō Asanuma", when Asanuma visited the U.S. Embassy on 24 May 1960 after the forced vote on the Security Treaty, MacArthur strongly demanded retraction, but Asanuma refused, stating "There is no need to retract. This is not an attack on the American people; fighting imperialist policy is natural for the Socialist Party." Scholars suggest Asanuma's statement reflected repentance for damage caused to Chinese people by Japan's participation in aggression since the
Mukden Incident. Reportedly, Hirosawa prepared milder alternatives like "issue" instead of "enemy", but Asanuma deliberately chose "enemy". However,
Seiichi Katsumata claimed the phrase "American imperialism is the common enemy of the peoples of Japan and China" originated with Chinese leader
Zhang Xiruo, and Asanuma merely agreed, saying, "Well, yes..."
Chairman of the JSP In 1960, when
Suehiro Nishio and others left the JSP to form the
Democratic Socialist Party, chairman Mosaburō Suzuki resigned and Asanuma was elected his successor. In his role as JSP chairmain, Asanuma became one of the leading figures in the
1960 Anpo protests against the
US-Japan Security Treaty. On 24 May 1960, he visited the U.S. Embassy to request postponement of President
Dwight D. Eisenhower's planned visit to Japan and engaged in a heated debate with the ambassador over "American imperialism". In the face of massive, nationwide popular protests, Prime Minister
Nobusuke Kishi was forced to resign and Eisenhower's visit was cancelled, although the Security Treaty was not scrapped. In July 1960, shortly after the end of the Anpo protests, Prime Minister
Nobusuke Kishi was stabbed six times in the left thigh by right-wing activist Taisuke Aramaki at the Prime Minister's Official Residence, sustaining serious but non-fatal injuries. Despite their intense political rivalry, Asanuma personally visited Kishi to offer condolences and inquire about his condition. As a politician, Asanuma cultivated an "everyman" image. He lived modestly in public housing his entire life, and was particularly popular among ordinary laborers, small shopkeepers, and other members of the
working class. In contrast to his pro-war stance during World War II, in the postwar period, Asanuma spearheaded the JSP's staunch opposition to revising
Article 9 of Japan's postwar constitution and remilitarizing Japan. However, historian
Andrew Gordon argues that Asanuma was consistent in his antipathy to western imperialism and a desire for Asia to chart its own course in world affairs. According to former Mainichi Shimbun reporter Michio Ozaki, who, as a young Waseda University student and member of the Waseda Political Studies Society, visited the Diet Members' Hall to pay annual dues for a supporting membership during the height of the 1960 Anpo protests, Asanuma displayed a warm and approachable personality, laughing off rumors while shaking with laughter in his large frame. Asanuma casually remarked to the student about rumors that
Zengakuren might set the building ablaze, laughing heartily as he noted that other Diet members had vanished. He added, "The next election will be in Shinjuku, so please support me." On 4 September 1960, just over a month before his assassination, Asanuma visited the Rinzai Zen temple Kinryū-ji in Azumino City, Nagano Prefecture. He delivered a public lecture there as part of his tireless grassroots speaking schedule. During the event, he performed calligraphy of the classic Zen phrase
Nichinichi kore kōnichi (Every day is a good day), a well-known saying attributed to the Chinese Zen master
Yunmen that emphasizes mindfulness, gratitude, and finding value in ordinary daily life. Following Asanuma’s death, local residents who had attended the lecture erected a stone monument on the temple grounds reproducing his calligraphy as a memorial. ==Assassination==